It is known to investigate samples at a multiplicity of locations thereon with electromagnetic beams, by applying ellipsometer and polarimeter systems. One approach is disclosed in a Patent to Johs et al., U.S. Pat. No. 7,277,171, which describes mounting an ellipsometer, polarimeter, reflectometer and the like on a means for enabling its motion in “X”, “Y” and “Z” directions. Another approach is described in Patents to Finarov, (eg. U.S. Pat. No. 5,517,312, RE38,153) which describes providing a stationary ellipsometer and applying movable beam directing means to direct an electromagnetic beam to a multiplicity of locations on a sample, but the Finarov Patents are silent as to correcting effects of said beam direction on polarization state.
Before preceding, for general insight it is also noted that ellipsometer and polarimeter systems generally comprise Polarization State Generation (PSG) and Polarization State Detection (PSD) systems configured such that the (PSG) directs a polarized beam of electromagnetic radiation toward a sample, and the (PSD) detects a beam which emerges from said sample after interaction therewith. It is noted that the present invention provides utility in that the (PSG) and (PSD) can be oriented closely next to one another because of the operation of first and second dual reflection surface means, (eg. prisms). This enables convenient application to environmental chambers in which, for instance, deposition onto or etching from a sample is practiced. It is often difficult to provide a retrofit ellipsometer system to such chambers, and it all can be, for instance, through a single window, that can greatly simplify the task of performing, for instance, sample mapping.
Continuing, it is also mentioned that ellipsometric PSI and DELTA refer to well known changes in a ratio of polarized beam orthogonal components and phase angle therebetween, respectively, induced by interaction of the polarized electromagnetic beam with the sample.
Because the present invention can be practiced with beam directing means that operate based on Total Internal Reflection, or on Specular reflection, it is also disclosed that U.S. Pat. Nos. 6,034,777, 6,549,282 and 6,804,004 describe methodology for correcting polarizations state effects introduced by beam directing means that rely on specular reflection so that uncorrelated PSI and DELTA of a Sample being investigated can be achieved. Also, U.S. Pat. No. 5,969,818 and describes a four bounce mirror system which performs orthogonal component compensation, and U.S. Pat. No. 5,963,327 to He et al. and Published Application US 2004/0070760 by Stehle ey al. describe an ellipsometer or the like in which beam directing means allow a source and detector to be positioned side by side rather than distally from one another along the locus of a sample investigating beam. However, no known reference discloses a dual prism means configured to provide a polarized output beam in a “X”-“Z” plane, by re-directing an input beam which enters thereinto along a “Y” axis, in an “X”-“Y”-“Z” coordinate system which substantially compensates any effects on a Polarization State of a polarized beam of electromagnetic radiation entered thereinto.
The references identified above are all incorporated by reference into this Disclosure.